1. Technical Field
The present invention relates to the extraction of flavour enhancers, which impart a kokumi sensation to foods. In particular, the present invention relates to specific peptides extracted from one or more edible plants and their use as flavour enhancers.
2. Description of Related Art
The food industry generally recognizes five basic tastes: sweet, salty, sour, bitter, and (most recently, as early as the 1990s) umami, which imparts a “brothy”, “meaty”, or “savoury” taste and is commonly associated with monosodium glutamate (MSG) and MSG-like tastes. The term “kokumi,” on the other hand, is used in the food industry to refer to enhanced flavour sensations such as long lasting taste development (mouthfulness, continuity, duration and depth); punch (relating to the initial taste and impact); and roundness and balance (richness, thickness, spread, and unity). The kokumi sensation is a distinct flavour enhancing sensation that cannot be expressed by any of the five basic tastes alone. As such, the terms “taste” and “flavour” as used herein are meant to describe different properties, although they can be complimentary. Taste involves the detection of one of the five basic tastes. Flavour, on the other hand, is a combination of one or more tastes and/or sensations experienced at the same time. In particular, flavour includes both taste and smell, and can also include sensations such as vision and expectation or the like. Thus, a kokumi flavour-enhancing sensation or effect is obtained when enhancing and expanding (or multiplying) the basic tastes as well as the tastes and senses peripheral to the basic tastes including without limitation aroma, food texture, long-lasting taste development, balance and punch.
A number of attempts have been made to produce a kokumi sensation. These various attempts have revealed a variety of sulfur-containing amino acids, peptides, and γ-glutamyl peptides, which are usually tasteless on their own but provide a kokumi sensation or effect when added to various tastes such as MSG, ribonucleotide solutions (including nucleotides 5′-inosine monophosphate (IMP) and 5′-guanosine monophosphate (GMP)), or beef extracts. In particular, a number of organosulfur compounds isolated from onions (Allium cepa) and garlic (Allium sativum L.) have been shown to impart flavour enhancing sensations when combined with savoury compositions or food products. However, currently known flavour enhancers do not fully satisfy neutral taste and are not very potent. Prior art methods typically focus on isolation of compounds from the leaves of these plants, which tend to add a flavor of their own.
Consequently, there remains a need for kokumi compounds that enhance flavor, without adding a flavor of their own. There is also a need for more potent and effective kokumi compounds, while using natural extracts. In particular, there is a need for kokumi compounds that utilize the potential flavour content of other, often ignored, parts of an edible plant and methods for extracting and purifying flavouring enhancing compounds from other edible plants, in order to prepare foods having an increased kokumi sensation.